Can I Build an ADU on My Property in San Diego? Here’s How to Find Out
Building an Accessory Dwelling Unit (ADU) is one of the best ways to increase your property’s value, create extra living space, or generate passive rental income. And with updated California laws and San Diego’s ADU-friendly policies, it’s easier than ever to get started—if your property qualifies.
So, how do you know if you can build an ADU on your property in San Diego? At Romex Design, we specialize in helping homeowners like you understand what’s possible—before you waste time or money.
Here’s a simple breakdown to help you find out.
What Is an ADU?
An ADU is a secondary residential unit on a single-family or multi-family property. These can include:
Detached ADUs: Built as a standalone structure in your backyard
Attached ADUs: Physically connected to your main home
Garage Conversions: Transforming an existing garage into living space
Junior ADUs (JADUs): Small units (up to 500 sq ft) within the main house
Each type has its own rules—but the good news is, most residential properties in San Diego are eligible for at least one type of ADU.
Step 1: Check Your Zoning and Lot Type
Most properties zoned for single-family or multi-family residential use are eligible to build at least one ADU. You can start by:
Looking up your address on the City of San Diego Zoning Map
Confirming your zoning designation (e.g., RS-1, RM-1, etc.)
Verifying your lot size and current structures
Romex Design offers free property assessments to help you determine feasibility faster—with expert insight into setbacks, lot coverage, and ADU design strategies.
Step 2: Understand ADU Regulations in San Diego
San Diego has adopted California’s ADU laws, which include:
No minimum lot size requirement
Setback requirements: Typically 4 ft from the rear and side property lines for detached units
Maximum size:
Up to 1,200 sq ft for detached ADUs
Up to 50% of the main home for attached ADUs
No owner-occupancy requirement (until 2025, when it may return)
No impact fees for ADUs under 750 sq ft
Each property is unique, so working with a knowledgeable design team like Romex Design ensures you take full advantage of what’s possible.
Step 3: Consider Site Conditions and Access
Even if your zoning allows an ADU, your site conditions will affect your design:
Slope or hillside lots may require engineering
Utility access (sewer, water, electrical) must be considered
Privacy and access for tenants or family members
Historic designations may add restrictions
Romex Design evaluates all of these factors up front and creates ADU designs that are both functional and buildable—with your specific property in mind.
Step 4: Talk to a Design Expert
Before you call a contractor or submit a permit, start with an architectural designer. At Romex Design, we:
Provide a site feasibility review
Create custom, code-compliant plans
Prepare Title 24 energy reports
Submit your designs to the City of San Diego for permit approval
Connect you with trusted builders and financing options if needed
This helps you avoid costly delays and ensures your ADU is designed for success from day one.
Final Thoughts: Yes, You Probably Can—And We’ll Help You Know for Sure
Most San Diego homeowners can build an ADU—but knowing how, where, and what type is key. That’s where Romex Design comes in. We simplify the process, explain your options, and give you the tools to move forward confidently.
Want to Find Out if Your Property Qualifies?
Contact Romex Design today for a free ADU consultation and discover what’s possible on your property.
